Changes in growth performance and proximate composition in Japanese flounder during metamorphosis

Authors

  • M. A. R. Hossain,

    Corresponding author
    1. Laboratory of Marine Stock-enhancement Biology, Division of Applied Bioscience, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan and
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  • M. Tagawa,

    1. Laboratory of Marine Stock-enhancement Biology, Division of Applied Bioscience, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan and
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  • R. Masuda,

    1. Fisheries Research Station, Kyoto University, Naga-Hama, Maizuru, Kyoto, 625-0086, Japan
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  • M. Tanaka

    1. Laboratory of Marine Stock-enhancement Biology, Division of Applied Bioscience, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan and
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†Present address: Department of Fish Biology and Genetics, Faculty of Fisheries, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh. Tel.: +880 91 54963; fax: +880 91 55810; email: marhossain@yahoo.com

Abstract

Morphological changes are described in Japanese flounder Paralichthys olivaceus larvae and juveniles with emphasis on growth during the period of metamorphosis. Ontogenetic changes in condition factor and lipid, glycogen and protein levels were also analysed to determine the utilization of stored energy. Fish grew from 6·6 to 20·3 mm LT(1·15 to 84·4 mg in mass, M) during the period from 11 to 40 days after hatching (DAH) at 19·3° C. Per cent specific growth rate per day (%G day−1) for wet mass was lowest during the metamorphic phase (21–30 DAH) compared to pre-(11–20 DAH) and post-metamorphic (31–40 DAH) phases. When LT and M were expressed as inline image, the b value was highest during the pre-metamorphic phase and lowest during the metamorphic phase. These findings indicate that the developmental changes that occur during metamorphosis of Japanese flounder are closely related to the growth pattern. Moisture, lipid and glycogen contents were also at the lowest level during metamorphosis compared to pre- and post-metamorphosis, which suggest that Japanese flounder use their energy reserves to accomplish metamorphosis due to an apparent decline in feeding during this period.

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